Neurotrophins and neuronal migration in the developing rodent brain

Role of vitamin D in the association between pre-stroke sleep quality and poststroke depression and anxiety

PURPOSE

Poor sleep quality, mood disorders, and vitamin D deficiency are common in stroke. We investigated the association between serum vitamin D levels and pre-stroke sleep quality and the occurrence of poststroke depression (PSD) and poststroke anxiety (PSA) in acute ischemic stroke (AIS).

METHODS

This prospective cross-sectional study included hospitalized patients with AIS and age- and sex-matched controls. Vitamin D levels were measured within 24 h of admission. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) at admission. The severity of depression and anxiety symptoms was evaluated according to Beck Depression Inventory and Beck Anxiety Inventory scores, respectively, within 72 h after admission.

RESULTS

Comparing 214 AIS patients with 103 controls, patients had significantly higher scores of Beck Depression Inventory, Beck Anxiety Inventory, and PSQI and lower vitamin D levels (p < 0.001). Among AIS patients, Beck Depression Inventory (p = 0.004) and Beck Anxiety Inventory (p = 0.018) scores were significantly higher in bad sleepers (PSQI score ≥ 6) than in good sleepers (PSQI score ≤ 5). Correlation analysis revealed negative correlations between serum vitamin D levels and Beck Depression Inventory (r =  - 0.234; p < 0.001), Beck Anxiety Inventory (r =  - 0.135; p = 0.016), and PSQI (r =  - 0.218; p < 0.001) scores.

CONCLUSION

Decreased serum vitamin D levels at admission are associated with a high risk for PSD and PSA in patients with poor pre-stroke sleep quality during the early stages of AIS.

The role of pro- and mature neurotrophins in the depression

Neurotrophic factors, which can provide nutritional support to neurons and neuronal cells, also played an important role in their proliferation and survival. As signaling molecules, it also mediated the learning, memory and other activities in the brain. The latest study shows that neurotrophic factors have diametrically opposing effects of the pro- and mature form through distinct receptors. In this review, we summarize the different forms of neurotrophic factors, related receptors, and the corresponding biological effects. More importantly, we expounded the physiology and pathology mechanisms of brain-derived neurotrophic factor(BDNF)in depression. It is hopefully to provide new idea on the relationship of neurotrophic factors and depression.

Levels of 25-hydroxyvitamin D3, biochemical parameters and symptoms of depression and anxiety in healthy individuals

Growing evidence support the role of vitamin D in brain function and behavior. This study investigated the relationship between 25-hydroxyvitamin D₃ [25(OH)D₃] levels, biochemical profile and symptoms of depression and anxiety in healthy individuals. Symptoms of depression were assessed by the Beck Depression Inventory (BDI) and anxiety was evaluated with the State-Trait Anxiety Inventory (STAI). Our sample included 36 individuals, mostly women 27(75%), 36.39 ± 9.72 years old, non-smokers 31(86.1%), body mass index of 26.57 ± 3.92 kg/m², 27.95 ± 7.50% body fat. Participants were divided into those with 25(OH)D₃ levels lower than 40 ng/mL (mean 28.16 ± 7.07) and equal or higher than 40 ng/mL (mean 53.19 ± 6.32). Those with lower 25(OH)D₃ had higher levels of triacylglycerol, triacylglycerol/high density lipoprotein (HDL) ratio, high glucose and homeostatic model assessment of insulin resistance (HOMA-IR) index. No changes were observed in sociodemographic variables, body composition, inflammatory parameters and cortisol. Additionally, in the groups with low and high 25(OH)D₃ levels, STAI state, STAI trait and BDI scores were not statistically different. Levels of 25(OH)D₃ were inversely and independently associated with glucose and HOMA-IR, but not associated with triacylglycerol, depression and anxiety scores. Lower levels of 25(OH)D₃ were associated with dysfunction in glucose metabolism but not with depression and anxiety in healthy individuals.

Vitamin D deficiency increases blood-brain barrier dysfunction after ischemic stroke in male rats

Because vitamin D hormone deficiency (VDH^def) can worsen severity and outcome for ischemic stroke, we examined the role of VDH in maintaining blood-brain-barrier (BBB integrity) in a rat model of stroke. In most types of stroke, the BBB is markedly compromised, potentially leading to a cascade of injury processes and functional deficits, so we examined a number of biomarkers associated with BBB disruption to determine whether VDH deficiency would further compromise the BBB following a stroke. Male Wistar rats were randomly assigned to one of two diet cohorts, VDH-sufficient (VDH^suf) and VDH^def. The VDH^suf group was fed standard rat chow and the VDH^def group got a VDH-null version of the same diet for 8 weeks. Animals from both cohorts were subjected to transient middle cerebral artery occlusion (tMCAO) surgery, killed at 72 h post-stroke, and their brains evaluated for BBB permeability and injury severity using expression of immunoglobulin (IgG), matrix metalloproteinase-9 (MMP-9) activity and alteration of tight junction (TJ) proteins as markers of BBB disruption. We also evaluated modulation of glucose transporter-1 (GLUT1), osteopontin (OPN), β-catenin and vitamin D receptor (VDR) expression in VDH^suf and VDH^def subjects. At the time of MCAO, rats on the VDH^def diet had circulating VDH levels one-fourth that of rats fed control chow. IgG extravasation after MCAO, indicating more severe BBB injury, was significantly higher in the MCAO+VDH^def than the MCAO+VDH^suf rats. Following MCAO, expression of MMP-9, GLUT1, VDR and OPN increased and the TJ proteins occludin and claudin-5 decreased significantly in the VDH^def compared to the VDH^suf group. We also observed significantly lower expression of β-catenin in the MCAO group of both VDH^suf and VDH^def rats. Under these conditions, VDH deficiency itself can compromise the BBB. We think that low serum VDH levels are likely to complicate stroke severity and its chronic consequences.

Repurposing and repositioning neurosteroids in the treatment of traumatic brain injury: A report from the trenches

The field of neuroprotection after brain injuries has been littered with failed clinical trials. Finding a safe and effective treatment for acute traumatic brain injury remains a serious unmet medical need. Repurposing drugs that have been in use for other disorders is receiving increasing attention as a strategy to move candidate drugs more quickly to trial while reducing the very high cost of new drug development. This paper describes our own serendipitous discovery of progesterone's neuroprotective potential, and the strategies we are using in repurposing and developing this hormone for use in brain injuries-applications very different from its classical uses in treating disorders of the reproductive system. We have been screening and testing a novel analog that maintains progesterone's therapeutic properties while overcoming its physiochemical challenges, and testing progesterone in combination treatment with another pleiotropic hormone, vitamin D. Finally, our paper, in the context of the problems and pitfalls we have encountered, surveys some of the factors we found to be critical in the clinical translation of repurposed drugs. This article is part of the Special Issue entitled 'Drug Repurposing: old molecules, new ways to fast track drug discovery and development for CNS disorders'.

Association Between Serum Levels of Vitamin D and the Risk of Post-Stroke Anxiety

Low levels of serum vitamin D are common in patients with mood disorders and stroke. It has been shown that low levels of serum vitamin D indicate a risk of depression in post-stroke subjects. Our aim was to determine the relationship between vitamin D and post-stroke anxiety (PSA).A consecutive series of 226 first acute ischemic stroke patients were recruited and followed up for 1 month. Serum levels of vitamin D were measured within 24 hours of admission. Patients with significant clinical symptoms of anxiety and a Hamilton anxiety scale score >7 were diagnosed as having PSA. In addition, 100 healthy subjects were recruited as controls and underwent measurements of serum vitamin D.A total of 60 patients (26.55%) showed anxiety at 1 month. Both PSA patients and non-PSA patients had lower serum levels of vitamin D than healthy subjects. A significant relationship was found between PSA and serum levels of vitamin D. Low serum levels of vitamin D (≤38.48 nmol/L) were independently associated with the development of PSA (OR: 2.49, 95% CI: 1.21-5.13, P = 0.01).Serum vitamin D status is related to the occurrence of anxiety in post-stroke patients and may be an independent risk factor of PSA after 1 month.

Transient receptor potential channels and their role in modulating radial glial-neuronal interaction: a signaling pathway involving mGluR5

The guidance of developing neurons to the right position in the central nervous system is of central importance in brain development. Canonical transient receptor potential (TRPC) channels are thought to mediate turning responses of growth cones to guidance cues through fine control of calcium transients. Proliferating and 1- to 5-day-differentiated neural progenitor cells (NPCs) showed expression of Trpc1 and Trpc3 mRNA, while Trpc4-7 was not clearly detected. Time-lapse imaging showed that the motility pattern of neuronal cells was phasic with bursts of rapid movement (>60 μm/h), changes in direction, and intermittent slow phases or stallings (<40 μm/h), which frequently occurred in close contact with radial glial processes. Genetic interference with the TRPC3 and TRPC1 channel enhanced the motility of NPCs (burst frequency/stalling frequency). TRPC3-deficient cells or cells treated with the TRPC3 blocker pyr3 infrequently changed direction and seldom contacted radial glial processes. TRPC channels are also activated by group I metabotropic glutamate receptors (mGluR1 and mGluR5). As shown here, pyr3 blocked the calcium response mediated through mGluR5 in radial glial processes. Furthermore, 2-methyl-6-(phenylethynyl)pyridine, a blocker of mGluR5, affected the motility pattern in a similar way as TRPC3/6 double knockout or pyr3. The results suggest that radial glial cells exert attractant signals to migrating neuronal cells, which alter their motility pattern. Our results suggest that mGluR5 acting through TRPC3 is of central importance in radial glial-mediated neuronal guidance.

Neurotrophin-3 gene transduction of mouse neural stem cells promotes proliferation and neuronal differentiation in organotypic hippocampal slice cultures

BACKGROUND

The transplantation of neural stem cells (NSCs) has been accepted as a promising therapeutic strategy for central nervous system disorders. However, the beneficial effect of NSC transplantation upon functional recovery is limited due to the unfavorable microenvironment (niche) at the site of trauma or degenerative disease in the brain. Combination of transplantation of NSCs with neurotrophins may overcome the hurdles of impaired cell survival and neuronal differentiation.

MATERIAL/METHODS

In the current study, the neurotrophin-3 (NT-3) gene was transduced into cultured mouse embryonic cortical NSCs via an AAV vector (NSC-NT-3). The effect of NT-3 over-expression on cell proliferation and differentiation in NSCs was observed by immunohistochemistry, cell culture and organotypic hippocampal slice cultures.<br />

RESULTS

The characteristics of self-renewal and multiple differentiation of NSCs were well-preserved. Cells in the NSC-NT-3 group proliferated faster and differentiated into more β-tubulin III-positive neurons compared to the control group in vitro. Furthermore, cells in the NSC-NT-3 group survived in a significantly higher percentage and undertook neuronal differentiation preferably in organotypic hippocampal slice cultures.

CONCLUSIONS

Our results suggest that the transduction of NT-3 into NSCs could effectively promote NSCs survival, proliferation, and neuronal differentiation in vitro without change of the stemness of NSCs. This work also offers evidence to better understand the safety and efficiency of combined treatment with NT-3 and NSCs for the central nervous system disorders.

The effects of vitamin D on brain development and adult brain function

A role for vitamin D in brain development and function has been gaining support over the last decade. Multiple lines of evidence suggest that this vitamin is actually a neuroactive steroid that acts on brain development, leading to alterations in brain neurochemistry and adult brain function. Early deficiencies have been linked with neuropsychiatric disorders, such as schizophrenia, and adult deficiencies have been associated with a host of adverse brain outcomes, including Parkinson's disease, Alzheimer's disease, depression and cognitive decline. This review summarises the current state of research on the actions of vitamin D in the brain and the consequences of deficiencies in this vitamin. Furthermore, we discuss specific implications of vitamin D status on the neurotransmitter, dopamine.

Growth factors in ischemic stroke

Data from pre-clinical and clinical studies provide evidence that colony-stimulating factors (CSFs) and other growth factors (GFs) can improve stroke outcome by reducing stroke damage through their anti-apoptotic and anti-inflammatory effects, and by promoting angiogenesis and neurogenesis. This review provides a critical and up-to-date literature review on CSF use in stroke. We searched for experimental and clinical studies on haemopoietic GFs such as granulocyte CSF, erythropoietin, granulocyte-macrophage colony-stimulating factor, stem cell factor (SCF), vascular endothelial GF, stromal cell-derived factor-1α and SCF in ischemic stroke. We also considered studies on insulin-like growth factor-1 and neurotrophins. Despite promising results from animal models, the lack of data in human beings hampers efficacy assessments of GFs on stroke outcome. We provide a comprehensive and critical view of the present knowledge about GFs and stroke, and an overview of ongoing and future prospects.